1. Field of the Disclosure
This disclosure relates generally to drilling systems that include sensors for providing measurements relating to a parameter of interest, and, more specifically, to sensors located on a drill string.
2. Background of the Related Art
Oil wells (wellbores) or boreholes are usually drilled with a drill string that includes a tubular member having a drilling assembly (also referred to as the bottomhole assembly or “BHA”) with a drill bit attached to the bottom end thereof. The drill bit is rotated to disintegrate the earth formation to form the wellbore. The drill string and BHA include devices and sensors for providing information about a variety of parameters relating to the drilling operations (drilling parameters), behavior of the BHA (BHA parameters) and formation surrounding the wellbore being drilled (formation parameters). Drilling parameters include weight-on-bit (“WOB”), rotational speed (revolutions per minute or “RPM”) of the drill bit and BHA, rate of penetration (“ROP”) of the drill bit into the formation, and flow rate of the drilling fluid through the drill string. The BHA parameters typically include torque, whirl, vibrations, bending moments and stick-slip. Formation parameters include various formation characteristics, such as resistivity, porosity and permeability, etc.
Sensors for determining force and torque are located on downhole portions of the drill string, BHA, tools or other portions of the drilling system. The sensors are attached by an adhesive to a tool or a mechanical member screwed onto the tool at the desired location. The adhesive may break down over time as the tool is exposed to high temperatures and pressures downhole. This can cause increased repair and maintenance costs.